by David Jackson, USA TODAY

by David Jackson, USA TODAY

WASHINGTON -- President Obama nominated new economic and environmental officials Monday, saying they will help grow the economy, increase sources of energy and reduce the threat of climate change.

"We've got a lot of work to do," Obama said during a nomination ceremony in the East Room at the White House.

Obama tapped Walmart executive and former Office of Management and Budget official Sylvia Mathews Burwell to be his new budget director.

Environmental Protection Agency official Gina McCarthy is being nominated to be EPA administrator, and MIT professor Ernest Moniz has been tapped to be the new Energy secretary, Obama said.

Part of their jobs will be to "control our own energy future, while reducing pollution which contributes to climate change," Obama said.

All three nominees must be confirmed by the Senate.

In introducing his new budget director, Burwell, Obama cited her biggest immediate challenge: the sequester, $85 billion in automatic budget cuts over the next seven months that began over the weekend. Those cuts will affect both domestic and national defense programs and create pain throughout the economy, Obama said.

The president said he is confident Burwell and her team "will do everything in their power to blunt the impact of these cuts on businesses and middle-class families -- but eventually a lot of people are gonna feel some pain."

Burwell, who currently runs the Walmart Foundation, served as deputy budget director from 1998 to early 2001 during Bill Clinton's presidency.

"She was one of the principal architects of a series of budget plans that produced a budget surplus, proving her ability to navigate the intricacies of the budget process and to work in a bipartisan way to produce results," a White House statement said.

If confirmed by the Senate, Burwell would replace acting OMB Director Jeffrey Zients, who will retain his job as the administration's chief performance officer.

Sen. Jeff Sessions, R-Ala., top Republican on the Senate Budget Committee, said Burwell's nomination will be evaluated "fairly and thoughtfully," but added: "Whoever holds this office must be a strong leader, must be independent-minded, and must know that this is a management office and not a political one."

As for the environmental appointments, McCarthy is currently the EPA's assistant administrator for the Office of Air and Radiation. If confirmed by the Senate, she would replace EPA Administrator Lisa Jackson.

Some conservative groups questioned McCarthy's appointment, saying she has backed onerous regulations that threaten energy development and economic growth.

"McCarthy's confirmation would mean higher electricity prices for all Americans and a harsh regulatory environment for energy producers," said a statement from the Independent Women's Forum.

Environmental groups applauded the selection of McCarthy. The National Audubon Society called McCarthy "whip-smart, tough-talking, and tenacious" and said "she is exactly the kind of leader the country needs to make historic progress on climate change solutions."

Moniz was undersecretary for Energy 1997-2001 during the Clinton administration; he also also served on Obama's Science and Technology Advisory Council. Moniz would replace outgoing Energy Secretary Steven Chu.